|根号2-根号3|+|根号3-2|+|2-根号5| =√3-√2+2-√3+√5-2=√5-√2
绝对值等于：根号3-根号2+2-根号3+根号5-2，把正负根号3和正负2互相约掉，答案是：根号5-根号2
